Various guide systems are known for spatially positioning an instrument. In medical technology, for example, the task is present for surgeons to position a surgical microscope in various spatial degrees of freedom with the surgical microscope being mounted on a support.
For this purpose, published German patent application 4,032,207 discloses mounting a surgical microscope on a motorized positioning multi-link mechanism. With the aid of this multi-link mechanism, it is possible for the surgeon operating the mechanism to position the surgical microscope in space as desired without exerting force. However, the positioning of the microscope takes place via a separate control unit wherein the desired spatial coordinates of the surgical microscope must be inputted manually. Accordingly, a defined positioning during surgery is most difficult with an arrangement of this kind because the surgery must be interrupted to manually input specific spatial coordinates.
Furthermore, it is known in medical technology to spatially position surgical microscopes, which are mounted on conventional supports, with the aid of mechanical means. For example, in U.S. Pat. No. 3,887,267, a mouthpiece is disclosed with which the surgeon guides the surgical microscope during the surgery. The rigid connection between the head of the surgeon and the surgical microscope as well as the necessary expenditure of effort to move the support make a positioning of this kind however likewise very difficult.
U.S. Pat. No. 4,989,253 discloses an arrangement for contactlessly guiding a surgical microscope wherein the surgical microscope is moved with the aid of a voice-activated guide system. With this arrangement, significant disadvantages of the above-described guidance and positioning systems are avoided; however, difficulties result with respect to the precise determination of the particular travel path by the surgeon. The matching of the reaction times of the voice-sensitive positioning system to the corresponding voice signals is complex or possible only with difficulty.